1. Field of the Invention
The invention relates to a method and system for injecting a fluid into a patient from a bulk container, and in particular to a method and system for so injecting or infusing contrast fluid which does not require disposal of the entire system, including the fluid supply container, after each patient use.
2. Description of Related Art
In the field of medical imaging, many procedures require the use of a contrast agent that is intravenously delivered to the patient, generally through the use of an associated power injector that controls the delivery rate and volume and predeterminately limits the pressure at which the contrast fluid is delivered. The current norm is to employ a disposable syringe that is bulky and costly, and a filling procedure that is difficult and time consuming. The syringe is intended for only a single use and is accordingly disposed of after each patient use. Present protocols also require that any contrast fluid that remains in the bottle or container of contrast fluid, once the container has been opened for use and/or fluid has been loaded into a syringe, be discarded. Since the contrast fluid is typically delivered in bulk containers which may hold far more fluid than is used for most imaging procedures, this often requires the disposal of a volume of yet unused contrast fluid. This entire process is thus extremely wasteful and costly to the medical system as a whole.
It is an accordingly the desideratum of the invention to avoid, or at least significantly reduce, the drawbacks and difficulties that are present in the use of prior art methods and apparatus, as for example hereinabove described, for the delivery of contrast fluid to a patient in medical imaging procedures.
It is a particular object of the invention to provide such a method and system that enables a technician to readily load a syringe and prepare for delivery of a contrast fluid to a patient in a simplified yet highly intuitive manner.
It is another object of the invention to provide such a method and system having a first part, into which contrast fluid from a bulk container is loaded, that can be used repeatedly with multiple patients without jeopardizing sterility of the system or remaining supply of contrast fluid, and a second part that is intended for a single use with a single patient.
It is a further object of the invention to provide such a two part system in which the relative manufacturing cost of the second, single-use part is considerably less than the manufacturing cost of the first, multiple-use part, thereby maximizing efficient management of contrast fluid delivery costs for the health care provider.
It is still another object to provide such a method and system in which the single-use disposable part, which is replaced for each patient, is relatively simple to use and inexpensive to manufacture yet provides high reliability and operating integrity.
The present invention is based on and requires reliable maintenance of fluid flow, in at least that portion of the inventive apparatus into which contrast fluid is loaded from the fluid container or source, in a single direction toward the patient while preventing all potentially-contaminating reverse flow, so that contamination of the syringe and of the bulk contrast source can be prevented. Toward that end, a system constructed in accordance with the invention includes a first or filling section which attaches to the bulk contrast source (and to the power syringe), and a second or delivery section that is connected between and communicates contrast fluid from the filling section to the patient. In this manner any possibility of contamination between the delivery section and the filling section is prevented. It is generally contemplated that the filling section will be used for multiple patients during an entire day of imaging procedures or operations, whereas the delivery section will be discarded and replaced after each patient use.
The filling section includes a main body that can be attached to any existing power or manually-operated syringe or injector, and the body defines a fluid holding chamber having an inlet and an outlet for the contrast fluid. The inlet is connected to a conventional or otherwise suitable vented spike, which is routinely used to pierce a contrast fluid container to access its contents for transfer of the contained fluid to another device, as by or through a coiled length of sterile medical tubing. The inlet is provided or associated with a gravity-operated valve formed by a stainless steel ball which seats in a conically-profiled ring or lip that surrounds or bounds the inlet. The ball rolls disengagingly off or away from the valve seat to thereby open the inlet when the main body is vertically tilted or oriented, whereupon the technician can use or operate the syringe to draw contrast fluid from the container into the filling section fluid chamber, and to then purge (back through the inlet) any air which has collected at the top of the fluid chamber. A spring loaded one-way check valve in or at or proximate the outlet insures that the purged air is directed toward the contrast container rather than downstream, toward the patient, to the delivery section of the inventive apparatus. The main body is then rotated or reoriented so that the contrast fluid outlet is disposed lower than the opposite end of the main body to which the syringe is connected, thereby activating or closing the gravity-operated ball valve and sealing closed the fluid path between the fluid holding chamber of the filling section and the contrast container. This orientation of the filling section additionally insures that any air that may yet be present in the fluid chamber rises to and remains at that portion of the main body to which the syringe is attachedxe2x80x94i.e. remote from the outlet through which the contrast fluid is transferred to the delivery section of the apparatusxe2x80x94to thereby prevent unintended and potentially fatal injection of air into the patient. The filling section is then ready to be connected to the delivery section for injection or infusion of the contrast agent into the patient.
The delivery section includes a first fluid conduitxe2x80x94such as coiled, flexible, sterile tubingxe2x80x94having a first end that is attached to the outlet of the main body via at least one one-way check valve, and a second end that is attached to the inlet of an inline aspiration syringe. The aspiration syringe has a fluid chamber which is filled via an inlet and an outlet which is attached to a catheter by a second or delivery conduit in the form of another length of flexible, sterile, typically coiled tubing. The entire delivery system receives contrast fluid for infusion into the patient by means of the power or manually-operated loading syringe that is connected to the main body of the filling section. The aspiration syringe itself includes a spring loaded plunger which is used to confirm patency of the fluid path by manually depressing the plunger against the urgency of the spring and then releasing it to return the plunger to its initial position; patency is indicated by a visually-observable flow of blood from the patient into the second conduit for a distance of several inches. The process of injection or infusion, under the power of the main loading syringe, may then proceed. The aspiration syringe is furthermore constructed to avoid the need for additional valves, as have heretofore been required, to separately close its inlet during the patency confirmation; the plunger itself blocks and thereby closes the inletxe2x80x94and thus prevents backflow into the first conduitxe2x80x94as the plunger is advanced from its initial position to inject contrast fluid into the patient and then returned to that initial position to draw a mixture of contrast fluid and patient blood back into the aspiration syringe fluid chamber. The delivery section or set is moreover low in cost, as contrasted with the relatively more costly and complex filling section, and is intended to be discarded and replaced after each patient use of the inventive apparatus.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.